Cushioning mechanism



Feb. 29, 1944. s E 1- AL 2,342,978

CUSHIONING -MEGI'IANI S M Filed March 20, 1941 INVENTOR BY John Ln ATTORNEY Hubert L. libmcq Patented Feb. 29, 1944 UNITED STATES PATENT OFFICE CUSHIONING MECHANISM Application March 20, 1941, Serial No. 384,234

8 Claims.

This invention relates to cushioning devices, and is particularly adapted for use in railway car trucks for snubbing oscillations of the bolster.

The cushioning device to which the invention is directed comprises a plurality of levers one end of each of which is pressed against a housing by a spring acting between the housing and the other end of each of the levers. The levers are fulcrumed intermediate their ends on a follower member having wedge surfaces engaging wedge surfaces on the levers. It is an object of the invention to provide an initial contact between the wedge surfaces at or substantially at the inner end of the lever arm. As will be hereinafter set forth in more detail such a construction prevents the levers from becoming positioned at an angle to the longitudinal center line of the device such as would unduly stress the housing at the open end thereof.

Another object of the invention is the provision of means adjacent the outer ends of the levers for maintaining the contact of the spring on the levers at or near said outer ends.

A further feature of the invention is in connection with the retaining means between the levers and housing wherein a novel arrangement is provided to assure engagement of the levers with the retaining means as wear takes place between the parts.

In the drawing:

Figure 1 is an elevational view partly in vertical section of a cushioning mechanism embodying our invention.

Figure 2 is an elevational view partly in vertical section of the device, taken at right angles to Fig. 1.

Figure 3 is a. horizontal sectional view, taken on line 33 of Fig. 1, the spring being shown in dot-dash lines.

Figure 4 is a partial plan view of the interlocking arrangement between the levers and retaining means. I

Figure 5 is a partial view in vertical section, showing the initial contact between the levers and follower; and

Figure 6 is a view similar to Fig. 5, il1ustrat ing undesirable contact between the levers and follower.

The lower follower or base member H! has a pair of oppositely sloping surfaces I l and an upwardly projecting lug I2 formed with upwardly and outwardly sloping surfaces l3. Each friction lever M has a laterally extending arm l5 and a longitudinally extending arm l6. Intermediate the ends of arms l5 and I6 each lever has a sloping surface I! adapted to engage one of surfaces H on base member II). On the rear side of each shoe is a sloping surface l8 adapted to engage one of surfaces I3 to limit relative movement between the levers and member III in one direction. Arm l5 of each lever is formed at its outer end with a horizontal surface l9 and surfaces 2!! sloping downwardly and outwardly on each side of surface Is. A spring 2! rests on surfaces is of the levers and inasmuch as surfaces 20 slope away from the bottom of the spring the contact between the spring and levers is at the greatest possible distance from the fulcrum point of the levers on base member ID.

A housing 22 has a flange 23 engaging one end of spring 2| and is formed with inner friction surfaces 24 in engagementwith friction surfaces 25 on arms lb of the levers. Adjacent one end of the housing is a wall 26 having an opening 21 for one end of retaining bolt 28. The head 39 of the bolt is received in recesses 30 of the levers. The upper end of arm 16 ofeach lever is cut away at 3| to receive a flange 32 extending from the opposite side of arm N5 of the other lever. As will be seen from Fig. l, flanges 32 overlie the shank end of head 29 of the bolt and, in addition to the portions 33 of arms l3, limit upward movement of the bolt. A nut 34 on the bolt bears against wall 26 to retain the housing, spring and levers in assembled relation.

As wear takes place on friction. surfaces 24 and 25 the levers slide down surfaces I I on base member I0 and the levers move farther apart. This movement can continue for a considerable period without impairing the function of flanges 32 of retaining the bolt head in the levers due to the large overlap of said flanges with head 29.

Projecting upwardly from base member III are lugs 35 which serve to position the levers laterally of the member and also are adapted to be engaged by surface36 of the housing to transmit oversolid blows from the housing to the base member. In making the parts for our device we have found that it is not practical without involving considerable expense to obtain accurate contact over the extent of surfaces l I, I! at the same time that surfaces 24, 25 are in engagement. We therefore prefer to provide initial contact between surfaces II and H, as illustrated in Fig. 5, where they are shown diverging downwardly and outwardly so that the contact between the lever and base member is along a line-substantially at 36 which is at or adjacent the inner side of the lever. In this manner the distance from fulcrum point 36 to the point of application of the force of spring 2| at A, is at a maximum. In this position surfaces 25 of arms it are in contact with surfaces 24 of housing 22, and as the housing is moved downwardly friction will be developed between surfaces 24 and 25.

If the contacting surfaces H and H of the levers and base member respectively diverge upwardly and inwardly as shown in Fig. 6, the fulcrum at 3! is much closer to the point of application of force A, thus shortening the lever arm and decreasing the amount of the force of the spring transmitted to surfaces 24, 25. Moreover, we have found with surfaces positioned as shown in Fig. 6 that there is a tendency for the bottom of the levers to slide down surface ll until surfaces H and 11 are in substant ally complete engagement. This places arms iii of the levers at an angle to the housing, with the result that contact of friction surfaces 25 occurs only at the bottom of the housing in the region indicated at 38. As the housing moves downwardly relative to the levers it is wedged over the levers and a bursting stress is set up around the bottom of the housing that may crack the latter member.

We have found that an angle of about three degrees between surfaces I! and IT, as shown in Fig. 5, will assure proper initial contact between the parts. In any event. it is undesirable to start out with contact between surfaces I l, I? as shown in Fig. 6. It will be understood that some wear will take place on surfaces H and I1 and eventually these surfaces may be in substantial engagement as shown in Fig. 1. However, so long as these surfaces diverge so that the initial contact is toward the inner part of the lever, as shown in Fig. 5, there will be no tendency of the levers to slide down surfaces H so as to be at an angle to the housing member and place said member under bursting stresses.

As normal wear occurs on the friction surfaces of the housing and levers the latter will slide down surfaces H on the base member so as to maintain proper area of contact between surfaces 24 and 25. It will be observed that clearance is provided between spring 2! and the outer surface 39 of the levers so that the latter may move outwardly as wear takes place on the friction surfaces.

The terms and expressions which we have employed are used as terms of description and not of limitation, and we have no intention, in the use of such terms and expressions, of excluding any equivalents of the features shown and described or portions thereof, but recognize that various modifications are possible within the scope of the invention claimed.

What we claim is:

1. In a cushioning mechanism. a base member having a plurality of plane surfaces thereon sloping upwardly and toward the center thereof, friction levers each having a plane surface initially engaging one of sa d first named surfaces only near the upper extremity thereof, each of said levers having a pair of arms substantially at right angles to each other, spring means operatively engaging one of said arms, and a housing having a flange engaging said spring means and interior surfaces frictionally engaging the other of said arms.

2. A cushioning mechanism having a base member with upwardly inclined surfaces, friction levers supported by said base member having upwardly inclined surfaces, a housing engaging one end of said levers, spring means between the other end of said levers and said housing, said inclined surfaces on said base member and levers diverging downwardly and outwardly so as to maintain the initial contact therebetween at the inner end of said surface on the levers and so as to initially provide clearance between the outer ends of said surface on each lever and the corresponding inclined surface on said base member.

3. A cushioning mechanism having a base member with upwardly inclined surfaces, friction levers supported by said base member each lever having a surface inclined upwardly at a different angle than said first named surfaces, a housing engaging one end of said levers, spring means between the other end of said levers and said housing, the angle between said surfaces on said base member and levers being such that the initial contact therebetween is at the inner extremity thereof so as to provide fulcrums for said levers removed as far as possible from the line of engagement of said spring means and levers.

4. A cushioning mechanism for railway cars comprising a base member, friction levers s1idably mounted on said base member, a housing frictionally engaging one end of said levers, a spring between the other end of said levers and said housing, retaining means having an enlarged end engaging said levers and an end engaging said housing, and means on the upper end of each of said levers adjacent said enlarged end extending from one of said levers into overlapping relation with another of said levers to maintain the lever engaging end of said retain ing means in position.

5. A cushioning mechanism for railway cars comprising a base member, a pair of friction levers slidably mounted on said base member, a housing frictionally engaging one end of said levers, a spring between the other end of said levers and said housing, retaining means having an enlarged end engaging said levers and an end engaging said housing, and integral means on the upper end of each of said levers adjacent said enlarged end extending from each of said levers into overlapping relation with another of said levers to maintain the lever engaging end of said retaining means in position.

6. A cushioning mechanism for railway cars comprising a base member, a pair of friction levers slidably mounted on said base member, a housing frictionally engaging one end of said levers, a spring between the other end of said levers and said housing, said levers being recessed on their inner sides, a retaining bolt having a head received in said recess, said housing having a transversely extending wall provided with an opening receiving said bolt, and integral means on the upper end of each of said levers extending laterally of said bolt into overlapping relation with the opposite lever to maintain said head in said recess.

7. A cushioning mechanism comprising a base member having upwardly and inwardly inclined surfaces thereon, friction levers supported by said base member each lever having an arm extending laterally outwardly and an arm extending vertically upwardly, a housing engaging said vertically extending arms, and spring means operatively engaging said laterally extending arms and said housing, said levers initially engaging said inclined surfaces towards the upper extremity thereof and being spaced from said surfaces towards the lower extremity thereof.

8. In a cushioning mechanism a base member having a pair of oppositely sloping surfaces thereon, friction levers engaging said surfaces, each of said levers having a vertically extending arm and a laterally extending arm, a housing frictionally engaging said vertically extending arms, spring means between said housing and said laterally extending arms, said levers initially engaging said sloping surfaces toward the upper extremity thereof and being spaced from said surfaces towards the lower extremity thereof, the upper surface of said laterally extending arms comprising a substantially horizlontal central portion engaging said spring means and a surface on each side of said central portion sloping downwardly away from said spring means.

HUBERT L. SPENCE.

JOHN L. ELER. 

